1. Field of the Invention
The invention relates to an image sensor structure.
2. Description of the Related Art
Referring to FIG. 1, a conventional image sensor includes a substrate 10, a frame layer 18, a photosensitive chip 26, a plurality of wires 28, and a transparent layer 34. The substrate 10 has a first surface 12 formed with signal input terminals 15, and a second surface 14 formed with signal output terminals 17 connected to BGA metallic balls 16, which are then electrically connected to a printed circuit board (not shown). The frame layer 18 has an upper surface 20 and a lower surface 22 bonded to the first surface 12 of the substrate 10 to form a cavity 24 together with the substrate 10. The photosensitive chip 26 is arranged within the cavity 24 formed by the substrate 10 and the frame layer 18 and is mounted on the first surface 12 of the substrate 10. Each of the plurality of wires 28 has a first terminal 30 electrically connected to the photosensitive chip 26, and a second terminal 32 electrically connected to a corresponding signal input terminal 15 of the substrate 10. The transparent layer 34 is placed on the upper surface 20 of the frame layer 18.
According to the above-mentioned structure, when the photosensitive chip 26 is made larger and plural wires 28 are to be bonded and electrically connected to the signal input terminals 15 of the substrate 10, the gap between the photosensitive chip 26 and the frame layer 18 will be reduced. If the designed gap is too small, the package processes cannot be performed. Therefore, when the photosensitive chip 26 is made larger, the substrate 10 has to be enlarged, which may not meet the miniaturized requirement of the product.
In view of the above-mentioned problems, it is an important object of the invention to provide an image sensor having a reduced volume and thus may be more practical.
An object of the invention is to provide an image sensor capable of facilitating the manufacturing processes and increasing the yield.
Another object of the invention is to provide an image sensor, which has a standard package volume and a photosensitive chip packed therein. The size of the chip may be changed without increasing the package volume of the image sensor.
Still another object of the invention is to provide an image sensor capable of simplifying the manufacturing processes and reducing the manufacturing costs, and thus making the image sensor more practical.
To achieve the above-mentioned objects, the invention provides an image sensor including a substrate, a frame layer, signal input terminals, a photosensitive chip, a transparent layer, a plurality of wires and a glue layer. The substrate has a first surface and a second surface opposite to the first surface. The frame layer is placed on the first surface of the substrate to form a cavity together with the substrate. The signal input terminals are formed on the frame layer. The photosensitive chip has plural bonding pads, and is placed on the first surface of the substrate and positioned within the cavity. The transparent layer is placed over the frame layer to define, in the cavity, at least one exposure area through which the bonding pads of the photosensitive chip are exposed. The wires penetrate through the at least one exposure area and electrically connect the bonding pads of the photosensitive chip to the signal input terminals on the frame layer. The glue layer covers the at least one exposure area to seal the plurality of wires. Thus, the above-mentioned image sensor may be manufactured easily and may be more practical.
The invention also provides another image sensor including a substrate, a frame layer, a photosensitive chip, a transfer medium, and a transparent layer placed over the frame layer. The substrate has a first surface and a second surface opposite to the first surface. The frame layer is placed on the first surface of the substrate to form a cavity together with the substrate. The photosensitive chip has plural bonding pads, and is placed on the first surface of the substrate and positioned within the cavity. The transfer medium is electrically connected to the bonding pads of the photosensitive chip for transferring signals from the photosensitive chip.